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Issue: AC not blowing very cold even when temp set to lowest and the center dial set to 3 blue dots. Also, the temperature from the vents gets progressively warmer from the left side of the car to the right (the drivers door vent was cool, left center vent not quite as cool, right center vent warm and the passenger side vent the warmest). No issues with erratic fan or anything like that, so issue is not with the FSU.

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" /><o:p></o:p>
Fix: Added one can of R134 coolant from AutoZone<o:p></o:p>
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Procedure: <o:p></o:p>
  • Purchase a can of R134, hose to attach to the low pressure port and a gauge. The specific one that I purchased was a complete all in one kit for $26.99 (18 oz)
<o:p> R134 Can-Hose-Gauge.jpg </o:p>



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  • Start car and turn the AC onto its coldest setting. <o:p></o:p>
  • Raise the hood and locate the low pressure AC port
<o:p> AC Low-High Pressure Ports.jpg </o:p>
<o:p> Low Pressure Port covered.jpg </o:p>



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  • (Note there are two on the left side of the car, one close to the radiator and the other about 1/3 way back towards the firewall. They are two different sizes with the low pressure being the smallest and the high pressure being much larger diameter).<o:p></o:p>
  • Clean the exterior of the low pressure port prior to removing cap.<o:p></o:p>
  • Remove cap on low pressure port
<o:p> Low Pressure Port.jpg </o:p>



<o:p></o:p>
  • Clean the low pressure port using compressed air to ensure nothing will be going in but the R134<o:p></o:p>
  • Check pressure by placing hose and valve onto low pressure port and adjust dial to put indicator to the current temperature outside (or of your garage)<o:p></o:p>
(Note, my pressure was a little low under 30 PSI and should have been between 30 and 40 PSI (outside temp was 70 degrees F)
<o:p> R134 to Low Port.jpg </o:p>



<o:p></o:p>
  • Follow directions on can to add the R134 (very straight forward and simple)<o:p></o:p>
  • Check pressure when done<o:p></o:p>
  • Screw cap back onto low pressure port<o:p></o:p>
  • Climb inside and prepare to freeze!!<o:p></o:p>
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The whole process took about 5 to 10 minutes and I now have icy cold air throughout the entire car!!!!<o:p></o:p>
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Now, it is possible that I have a leak but since the AC had worked fine all last summer and I didn't see any history of issues like this in any of the prior service history, I figured this was the best first step to take.<o:p></o:p>
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So, If you have a similar issue, give this a try first. I did not get a quote from the dealer or my local indy, but I have read that they will typically charge somewhere around $60 for this, and if this doesn't solve your problem at least you are out less than $30. Plus the hose and gauge are reusable so you simply buy a can the next time this happens.<o:p></o:p>
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I did not check the temperature before (or after) because I didn't have a thermometer handy, but trust me it feels like the difference between night and day.
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Anyway, I wanted to do this because I spent a few hours last night searching for this on both the board and via Google and found most of this, but not specifically for our car, so I figured I should provide a little payback to everyone for always helping me when I need something.<o:p></o:p>
 

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Thanks Jlusby. My A/C seems to be blowing cold, but I might try this to see if it helps reduce the noise from my A/C compressor. When I turn on the A/C, the compressor makes a low noise I can hear in the cabin. I'm hoping that the added lubricant that comes with the R-134a might help reduce the compressor noise.
 

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Lucky. Us Wisconsinites can't buy refrigerant unless you are an HVAC dealer. Apparantly we are too dumb to handle it. Well, I know i am, but that shouldn't restrict all the other residents here.

It is possible you developed a small leak, or even one of the valves (where you filled at) has gotten weak. You will know near the end of summer, or at the begining of next summer.

I can tell you, $29.99 will be much cheaper than having the leak diagnosed and fixed. Just keep doing that until it doesn't last a full season.

Bob
 

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Pardon this most likely lame question, but is R-134a the same refrigerant that the M5 shipped with? I'd like to check my system pressure before I bought this kit, but i bet you need a special gauge right?

Does this product allow the use of the gauge without cracking the seal on the can of refrigerant?
 

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Lucky. Us Wisconsinites can't buy refrigerant unless you are an HVAC dealer. Apparantly we are too dumb to handle it.
But I bet you're smart enough to buy it the next time you drive outside WI. ;)
 

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Pardon this most likely lame question, but is R-134a the same refrigerant that the M5 shipped with? I'd like to check my system pressure before I bought this kit, but i bet you need a special gauge right?
M5 uses R134a.

Professional style gauges show both high and low pressure. You can usually get away with just a low pressure gauge, but if you have to add more than one can, I would get it checked out by a pro, even if they only check the low and high side pressure.
Regards,
Jerry
 
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I have no issues with my A/C (that I know of), but that doesn't mean I'm not near the low end of the pressure range meaning my compressor is coming on more often then it should be. Was just thinking about adding a quick check of the pressure to my list. Too bad a car tire gauge doesn't fit on the low-pressure side.
 

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If I'm not mistaken, the lubricant for some parts of the A/C compressor are within the refridgerant, so a noisy compressor could be helped by adding a little more R134. I think the big hazard is adding too much, too fast and blowing the seals..A good rule of thumb, is if you add more than a pound and don't see the pressure coming up, the seals are probably gone..
 

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As would explain my 2 boxes of 134a and install kit sitting in my garage :grinyes:
REK lemme know (when you do this) if you're able to use the gauge w/o actually opening the can. If so I can buy one and use the gauge as a check. If I'm not low I could just return the kit no harm no foul.
 

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Discussion Starter #12
I believe you can use the gauge from the can without puncturing. I thought I actually checked that before I added the R134. I could check with my gauge as the can has been tossed. I will let you know what I find....
 

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If I'm not mistaken, the lubricant for some parts of the A/C compressor are within the refridgerant, so a noisy compressor could be helped by adding a little more R134. I think the big hazard is adding too much, too fast and blowing the seals..A good rule of thumb, is if you add more than a pound and don't see the pressure coming up, the seals are probably gone..
Lubricant is also sold separately, in much smaller cans.
Regards,
Jerry
 

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Discussion Starter #16
I tested this tonight with the gauge that came with the R134 (can is long gone) and I was able to read my pressure without issue. So I am sure you can just use the gauge without actually having to puncture the can.
 

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FYI

Refrigerant has oil in it as a carrier. You can buy oil by itself in small cans. I had the unfortunate luck of hunting down an a/c problem with our '03 Suburban last summer which required a compressor replacement and a few other odds and ends. I was able to "borrow" a vacuum pump from Auto Zone with a deposit on my credit card if I didn't return it(think it was about $400 pump). If you aren't in the know about a/c systems a vacuum pump is used to boil all of the moisture out of the system by placing it under vacuum.:checkeredflag:

When an a/c system is working well the low side will be cold to the touch. Watch out for the high side,it gets very hot with the freon under pressure.
:cool2:
 
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I've noticed that the cans of R-134A have different "PAG" numbers. Does anyone know which is the correct PAG value for our M5's?
 
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